This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Bacteriophages, herpesviruses and other large dsDNA viruses contain molecular machines that pump DNA into preassembled procapsids, triggering maturation with an associated cascade of particle size change, release of packaging enzymes, binding of proteins for cell association and activation of the particles for infection. These events are associated with capsid pressures exceeding, by 10-fold, that of bottled champagne, and are detected by a protein switch that transduces a signal from inside to outside of the particle.